Exercise equipment with automatic adjustment of stride length and/or stride height based upon direction of foot support rotation

ABSTRACT

The invention is an exercise device comprising (i) a frame, (ii) first and second foot supports operably associated with the frame for traveling in a forward and backward direction along a closed loop path relative to a transverse axis defined by the frame, (iii) a means effective for sensing the direction of travel of the foot supports along the closed loop path as between the forward and the backward directions, and (iv) a means for automatically adjusting the stride length and/or stride height of the closed loop path traveled by the foot supports based upon the sensed direction of travel of the foot supports.

FIELD OF THE INVENTION

This invention relates to exercise equipment, more specifically tostationary cardiovascular exercise equipment, and most specifically toelliptical exercise equipment.

BACKGROUND

One type of stationary cardiovascular exercise equipment which hasbecome extremely popular based predominantly upon its low-impact andnatural motion is the elliptical exercise machine. A wide variety ofelliptical exercise machines have been developed. Briefly, ellipticalexercise machines include foot supports supported upon foot links withthe foot links pivotally connected at a first end through a linkagesystem to a drive shaft for travel along a defined closed loop path(e.g., circular, elliptical, oval, etc.) and connected at the other endfor reciprocating motion along a defined path as the first end travelsalong the closed loop path. This combination of looping andreciprocating paths of travel at opposite ends of the foot links impartan “elliptical” type motion to the foot supports attached to the footlinks.

Some elliptical exercise machines permit a user to exercise in both aforward and a backward motion. While this feature enhances the value ofthe machine by permitting a user to employ a completely different motionwhich emphasizes different muscle and muscle groups, the machines do notalter the path of travel of the foot supports to accommodate theinherent difference in stride between a forward walking/running motionand a backward walking/running motion.

Accordingly, a need exists for elliptical exercise machines which permita user to exercise in both a forward and a backward motion and altersthe path of travel of the foot supports dependant upon whether the useris moving in a forward and backward direction in order to accommodatethe inherent difference in stride between a forward walking/runningmotion and a backward walking/running motion.

SUMMARY OF THE INVENTION

A first embodiment of the invention is an exercise device comprising (i)a frame, (ii) first and second foot supports operably associated withthe frame for traveling in a forward and backward direction along aclosed loop path relative to a transverse axis defined by the frame,(iii) a means effective for sensing the direction of travel of the footsupports along the closed loop path as between the forward and thebackward directions, and (iv) a means for automatically adjusting thestride length of the closed loop path traveled by the foot supportsbased upon the sensed direction of travel of the foot supports.

A second embodiment of the invention is an exercise device comprising(i) a frame, (ii) first and second foot supports operably associatedwith the frame for traveling in a forward and backward direction along aclosed loop path relative to a transverse axis defined by the frame,(iii) a means effective for sensing the direction of travel of the footsupports along the closed loop path as between the forward and thebackward directions, and (iv) a means for automatically adjusting thestride height of the closed loop path traveled by the foot supportsbased upon the sensed direction of travel of the foot supports.

A third embodiment of the invention is an exercise device comprising (i)a frame, (ii) first and second foot supports operably associated withthe frame for traveling in a forward and backward direction along aclosed loop path relative to a transverse axis defined by the frame,(iii) a means effective for sensing the direction of travel of the footsupports along the closed loop path as between the forward and thebackward directions, and (iv) a means for automatically adjusting thestride length and stride height of the closed loop path traveled by thefoot supports based upon the sensed direction of travel of the footsupports.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the invention.

FIG. 2 is a side view of the invention shown in FIG. 1 with theprotective housing removed and depicting a single foot link andassociated components.

FIG. 3 is an enlarged view of the forward portion of the invention shownin FIG. 2 depicting the first end portion of the foot link andassociated dynamic components.

FIG. 4 is an enlarged view of the rearward portion of the inventionshown in FIG. 2 depicting the second end portion of the foot link andassociated supporting components.

FIG. 5 is a side view of an alternate embodiment of the rear portion ofthe invention shown in FIG. 2 depicting a single foot link andassociated components.

FIG. 6 is a side view of a second embodiment of the invention withprotective housing removed and depicting a single foot link andassociated components.

FIG. 7 is an enlarged view of the forward portion of the invention shownin FIG. 6 depicting the first end portion of the foot link andassociated dynamic components.

FIG. 8 is an enlarged view of the rearward portion of the inventionshown in FIG. 6 depicting the second end portion of the foot link andassociated supporting components.

FIG. 9 is a perspective view of a third embodiment of the invention withthe protective housing removed to facilitate viewing of othercomponents.

FIG. 10 is a side view of the invention shown in FIG. 9 with theprotective housing removed and depicting a single foot link andassociated components.

FIG. 11 is an enlarged view of the forward portion of the inventionshown in FIG. 10 depicting the first end portion of the foot link andassociated dynamic components.

DETAILED DESCRIPTION OF THE INVENTION INCLUDING A BEST MODE

Nomenclature

-   10 Exercise Device-   20 Frame-   21 Front Stanchion Portion of Frame-   22 Rear Stanchion Portion of Frame-   30 Drive Shaft-   40 Crank Arm-   40 a First End of Crank Arm-   40 b Second End of Crank Arm-   50 Drive Pulley-   50 a Front Drive Pulley-   50 b Rear Drive Pulley-   60 Foot Link-   60 a First End of Foot Link-   60 b Second End of Foot Link-   61 p Closed Loop Path of Travel for One End Portion of Foot Link-   62 p Path of Travel for Other End Portion of Foot Link-   69 Roller on Foot Link-   70 Foot Support-   70 p Closed Loop Path of Travel for Foot Support-   80 Rocker Link-   80 a First End of Rocker Link-   80 b Second End of Rocker Link-   90 Connector Link-   90 a First End of Connector Link-   90 b Second End of Connector Link-   100 Brake-   110 Braking Control System-   120 Guide Rail-   121 Rear Guide Arm-   121 a First End of Rear Guide Arm-   121 b Second End of Rear Guide Arm-   130 Incline Adjustment System-   140 Master Control Unit-   150 User Interface Panel-   160 Rotational Direction Sensing System-   161 Magnet-   162 Magnetic Sensing Element-   171 First Pivot Point Repositioning Unit-   172 Pivot Point Repositioning Unit-   173 Pivot Point Repositioning Unit-   174 Pivot Point Repositioning Unit-   180 Inertia Generation System-   181 Flywheel-   182 Pulley (small diameter)-   183 Shaft-   184 Drive Belt-   221 Front Guide Arm-   221 a First End of Front Guide Arm-   221 b Second End of Front Guide Arm-   230 Linear Actuator-   310 Support Shaft-   320 Rocker Link-   320 a First End of Rocker Link-   320 b Second End of Rocker Link-   330 Drawbar-   330 a First End of Drawbar-   330 b Second End of Drawbar-   340 Timing Belt-   p₁ First End Foot Link Pivot Point-   p₂ Second End Foot Link Pivot Point-   p₃ Rocker Pivot Point-   p₄ Crank Pivot Point-   p₅ Front Guide Arm Pivot Point-   p₆ Rear Guide Arm Pivot Point-   p₇ Rocker-Foot Pad Pivot Point-   p₈ Rocker-Frame Pivot Point-   p₉ Drawbar-Rocker Pivot Point-   FWD Forward Rotation-   REV Backward Rotation-   SH Stride Height-   SL Stride Length-   x Lateral Axis-   x₁ First Lateral Direction-   x₂ Second Lateral Direction-   y Longitudinal Axis-   z Transverse Axis-   z₁ First Transverse Axis-   z₂ Second Transverse Axis    Definitions

As utilized herein, including the claims, the phrase “extension element”includes any component attached to and extending substantiallyorthogonally from a drive shaft by which circular motion is imparted tothe drive shaft. Exemplary extension elements include specifically, butnot exclusively, a bent portion of a drive shaft, a crank arm, a drivepulley, and rigidly or pivotally attached combinations thereof.

As utilized herein, including the claims, the phrase “stride height”means the vertical distance between highest and lowest vertical pointsalong the path traveled by a foot support.

As utilized herein, including the claims, the phrase “stride length”means the linear distance between forward most and rearward most pointsalong the path traveled by a foot support.

Construction

As shown in FIGS. 1-11, the invention is an exercise device 10 includingat least (i) a frame 20 defining a transverse axis z, (ii) first andsecond foot supports 70 operably associated with the frame 20 fortraveling in a forward FWD and backward REV direction along a closedloop path 70 p relative to the transverse axis z wherein the closed looppath 70 p defines a stride length SL and stride height SH, (iii) a means160 effective for sensing the direction of travel of the foot supports70 along the closed loop path 70 p as between the forward FWD andbackward REV directions, and (iv) a means (not collectively numbered)for automatically adjusting the stride length SL and/or the strideheight SH of the closed loop path 70 p traveled by the foot supports 70based upon the sensed direction of travel of the foot supports 70.

As shown in FIGS. 1, 2, 6, 9 and 10, the frame 20 includes a base (notseparately numbered) for stably supporting the exercise device 10 on afloor (not shown), and a plurality of stiles, rails, stanchions andother supporting members (not separately numbered) as necessary andappropriate to operably support the components of the exercise device10.

As shown in FIGS. 2, 3, 6, 8, 10 and 1, a drive shaft 30 is supported bythe frame 20 for rotation about a transverse axis z. An extensionelement(s) (not collectively numbered) is rigidly attached to the driveshaft 30 and extends substantially orthogonally from the drive shaft 30.A variety of suitable extension element(s) are known to those skilled inthe art, including specifically, but not exclusively, bent end portions(not shown) of the drive shaft 30, a pair of crank arms 40, a drivepulley 50, etc.

As shown in FIGS. 2 and 3, when the extension elements are crank arms 40each crank arm 40 has a first end 40 a rigidly attached proximate atransverse end (not separately numbered) of the drive shaft 30 forimparting rotational motion of the crank arms 40 about the transverseaxis z to the drive shaft 30 and interlocking the crank arms 40.

As shown in FIGS. 6, 8, 10 and 11, when the extension element is a drivepulley 50 the drive pulley 50 is rigidly attached the drive shaft 30 atthe center (not separately numbered) of the drive pulley 50 forimparting rotational motion of the drive pulley 50 about the transverseaxis z to the drive shaft 30.

Foot supports 70 are supported upon first and second foot links 60. Thefoot supports 70 may be supported upon the foot links 60 at any pointalong the length (unnumbered) of the foot links 60 so long as the footlink 60 moves in a closed loop path at the point of connection(unnumbered). For example, the embodiment of the invention shown inFIGS. 1-4 laterally positions the foot supports 70 in the second lateraldirection x₂ from the point (not numbered) at which the foot link 60 issupported by the guide rail 120. The embodiment of the invention shownin FIGS. 6-8 positions the foot supports 70 between the point(unnumbered) at which the foot link 60 is pivotally connected to thecrank arm 40 and the point p₁ at which the foot link 60 is pivotallyconnected to the front guide arm 221. The embodiment of the inventionshown in FIGS. 9-11 positions the foot supports 70 between the point(unnumbered) at which the foot link 60 is pivotally connected to thefront drive pulley 50 a and the point (unnumbered) at which the footlink 60 is pivotally connected to the rear drive pulley 50 b. Otherembodiments are also possible.

The first and second foot links 60 may be associated with the frame 20in a variety of different ways to accomplish and impart the necessaryclosed loop path of travel to the foot supports 70 attached to the footlinks 60. Exemplary connective structures and arrangements are disclosedin U.S. Pat. No. 3,316,898 issued to Brown, U.S. Pat. No. 5,242,343issued to Miller, U.S. Pat. No. 5,352,169 issued to Eschenbach, U.S.Pat. No. 5,383,829 issued to Miller, U.S. Pat. No. 5,423,729 issued toEschenbach, U.S. Pat. No. 5,518,473 issued to Miller, U.S. Pat. No.5,529,554 issued to Eschenbach, U.S. Pat. No. 5,562,574 issued toMiller, U.S. Pat. No. 5,577,985 issued to Miller, U.S. Pat. No.5,611,756 issued to Miller, U.S. Pat. No. 5,685,804 issued to Whan-Tonget al., U.S. Pat. No. 5,692,994 issued to Eschenbach, U.S. Pat. No.5,707,321 issued to Maresh, U.S. Pat. No. 5,725,457 issued to Maresh,U.S. Pat. No. 5,735,774 issued to Maresh, U.S. Pat. No. 5,755,642 issuedto Miller, U.S. Pat. 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No. 6,629,909 issuedto Stearns et al., and U.S. Patent Application Publication No.2001/0011053 filed by Miller, U.S. Patent Application Publication No.2001/0051562 filed by Stearns et al., U.S. Patent ApplicationPublication No. 2002/0019298 filed by Eschenbach, U.S. PatentApplication Publication No. 2002/0055420 filed by Stearns et al., U.S.Patent Application Publication No. 2002/0128122 filed by Miller, U.S.Patent Application Publication No. 2002/0142890 filed by Ohrt et al.,U.S. Patent Application Publication No. 2002/0155927 filed by Corbaliset al., U.S. Patent Application Publication No. 2003/0022763 filed byEschenbach, which disclosure is hereby incorporated by reference.

One specific embodiment of a structure for operably interconnecting thefirst and second foot links 60 with the frame 20 is shown in FIGS. 1-4.This embodiment has (i) a first end portion 60 a of each foot link 60indirectly pivotally attached, through a connecting system (notcollectively numbered) to the second end 40 b of a crank arm 40 at apoint spaced from the transverse axis z for travel along a closed looppath 61 p relative to the transverse axis z, and (ii) a second endportion 60 b of each foot link 60 supported by a roller 69 upon a guiderail 120 for reciprocating travel of the second end portion 60 b of thefoot link 60 along a lateral path 62 p. An alternate embodiment forsupporting the second end portion 60 b of each foot link 60 to the frame20 is shown in FIG. 5, wherein the a second end portion 60 b of eachfoot link 60 is pivotally attached proximate the second end 121 b of arear guide arm 121, which is pivotally attached proximate a first end121 a of the rear guide arm 121 to the frame 20 at a rear guide armpivot point p₆ located above the foot link 60, for reciprocating travelof the second end portion 60 b of the foot link 60 along a lateral path62 p.

One suitable connecting system is shown in FIGS. 1-4. The depictedconnection system includes (i) a connector link 90 pivotally attached ata first end 90 a to the first end 60 a of the foot link 60 at a firstend foot link pivot point p₁ and pivotally attached at a second end 90 bto a second end 80 b of a rocker link 80 at a rocker pivot point p₃, and(ii) a rocker link 80 pivotally attached at a first end 80 a to theframe 20 and pivotally attached at the second end 80 b to the connectorlink 90 at the rocker pivot point p₃, wherein the crank arm 40 ispivotally attached at the second end 40 b to the connector link 90 at acrank pivot point p₄ which is positioned intermediate the first end footlink pivot point p₁ and the rocker pivot point p₃.

A second specific embodiment of a structure for operably interconnectingthe first and second foot links 60 with the frame 20 is shown in FIGS.6-8. This embodiment has (i) a first end portion 60 a of each foot link60 pivotally attached proximate the second end 221 b of a front guidearm 221, and pivotally attached proximate a first end 221 a to the frame20 at a front guide arm pivot point p₅ located above the foot link 60,for reciprocating travel of the first end portion 60 a of the foot link60 along a lateral path 62 p and (iii) a second end portion 60 b of eachfoot link 60 directly pivotally attached to a drive pulley 50 at a point(not numbered) spaced from the transverse axis z for travel along aclosed loop path 61 p about the transverse axis z.

A third specific embodiment of a structure for operably interconnectingthe first and second foot links 60 with the frame 20 is shown in FIGS.9-11. This embodiment is shown and described in detail in U.S. PatentApplication Publication No. 2002/0055420, the disclosure of which ishereby incorporated by reference. Briefly, this embodiment has (i) afirst end portion 60 a of each foot link 60 pivotally supported upon asupport shaft 310 which is attached to a front drive pulley 50 a at apoint (not numbered) spaced from a first transverse axis z₁ for travelalong a first closed loop path 61 p about the first transverse axis z₁,and (ii) a second end portion 60 b of each foot link 60 pivotallysupported upon a support shaft 310 which is attached to a rear drivepulley 50 b at a point (not numbered) spaced from a second transverseaxis Z₂ for travel along a closed loop path 62 p about the secondtransverse axis z₂. A foot support 70 is slidably supported upon eachfoot link 60 and operably engaged by a rocker link 320 for effecting areciprocating motion of the foot support 70 along the length of the footlink 60. Each rocker link 320 has a first end portion 320 a pivotallyconnected to a respective foot support 70 and a second end portion 320 bpivotally mounted on the frame 20. Movement of each rocker link 320 iscontrolled by a drawbar 330. Each drawbar 330 has a first end portion330 a constrained to travel in association with the respective foot link60 relative to the first and second closed loop paths 61 p and 62 p anda second end portion 330 b connected to a respective rocker link 320.The combination of a rocker link 320 and associated drawbar 330cooperate to transfer and link travel of the foot link 60 along thefirst and second closed loop paths 61 p and 62 p to longitudinal slidingof the respective foot support 70 along the respective foot link 60.

The exercise device 10 preferably include a system attached to the frame20 and in communication with the system through which the foot supports70 are operably associated with the frame 20, such as a brake 100 andbraking control system 110, for exerting a controlled variable resistiveforce against movement of the foot supports 70 along the closed looppath of travel 70 p. It is preferred to provide a separate resistancedevice for each foot support 70. Many types of resistance devices areknown such as pivoting devices, sliding devices, weights on cables orlevers, braking motors, generators, brushless generators, eddy currentsystems, magnetic systems, alternators, tightenable belts, frictionrollers, etc., any of which could be effectively utilized in the presentinvention. Exemplary resistance devices suitable for use in thisinvention include those disclosed in U.S. Pat. No. 5,423,729 issued toEschenbach, U.S. Pat. No. 5,685,804 issued to Whan-Tong et al., U.S.Pat. No. 5,788,610 issued to Eschenbach, U.S. Pat. No. 5,836,854 issuedto Kuo, U.S. Pat. No. 5,836,855 issued to Eschenbach, U.S. Pat. No.5,846,166 issued to Kuo, U.S. Pat. No. 5,895,339 issued to Maresh, U.S.Pat. No. 5,947,872 issued to Eschenbach, U.S. Pat. No. 5,957,814 issuedto Eschenbach, U.S. Pat. No. 6,042,512 issued to Eschenbach, U.S. Pat.No. 6,053,847 issued to Stearns et al., 6,090,013 issued to Eschenbach,6,146,313 issued to Whan-Tong et al., 6,217,485 issued to Maresh,6,409,632 issued to Eschenbach, 6,482,130 issued to Pasero et al.,6,544,146 issued to Stearns et al., 6,575,877 issued to Rufino et al.,and 6,612,969 issued to Eschenbach, which disclosure is herebyincorporated by reference.

The exercise device 10 also preferably includes an inertia generationsystem 180 attached to the frame 20 and in communication with the systemthrough which the foot supports 70 are operably associated with theframe 20. Such inertia generation system 180 are widely known andcommonly utilized on stationary exercise equipment. An exemplary inertiageneration system 180 is disclosed in U.S. Patent ApplicationPublication No. 2002/0055420, the disclosure of which is herebyincorporated by reference. This system is shown in FIGS. 1-3 and 9-11.Briefly, the system 180 includes a flywheel 181 and a relatively smallerdiameter pulley 182 which are rotatably mounted on opposite sides(unnumbered) of the front stanchion 21. The flywheel 181 is keyed to thesmall pulley 182 by a central shaft 183. A belt 184 is looped about thedrive pulley 50 (FIGS. 1-3) or 50 a (FIGS. 9-11) and the small pulley182 to effect rotation of the small pulley 182 when the drive pulley 50(FIGS. 1-3) or 50 a (FIGS. 9-11) is rotated by operation of the footlinks 60. As a result, the flywheel 181 rotates at a relatively fasterspeed than the drive pulley 50 (FIGS. 1-3) or 50 a (FIGS. 9-11) and addsinertia to the linkage assemblies.

The direction of travel of the foot supports 70 along the closed looppath 70 p as between the forward and the backward directions can bedetermined by a variety of systems known to those skilled in the artincluding specifically, but not exclusively, audible (sensing toneemitted when air moves through a device which emits different tones whenair enters from different directions), electrical (e.g., sensingpolarity of voltage), magnetic (e.g., sequence in which magnets onrotating element are sensed), mechanical (e.g., sensing position ofbiased toggle switch which is moved against the bias only when rotationis effected in one direction), visual (e.g., sequence in whichreflective patches on rotating element are sensed), etc.

Referring to FIGS. 2 and 3, one suitable system 160 for sensing thedirection of travel of the foot supports 70 along the closed loop path70 p as between the forward and the backward directions includes amagnet 161 attached to a face (unnumbered) of the flywheel 181 at apoint radially spaced from the shaft 183, and a pair ofcircumferentially offset magnetic sensing elements 162 (e.g., reedswitches) positioned proximate the face (unnumbered) of the flywheel 181for sensing the magnet 161 as the magnet 161 passes the magnetic sensingelement 162. Circumferential offsetting of the magnetic sensing elements162 (hereinafter referenced as A and B) means that the length of the arcbetween A and B when moving from A to B in the forward direction issensibly less (short pause) than the length of the arc between A and Bwhen moving from A to B in the backward direction (long pause). Bycircumferentially offsetting the magnetic sensing elements 162, thedirection of rotation can be determined from the sequence of detectingactivation of A, activation of B, long pause, and short pause. In theexample set forth above, a detected sequence of “A—short pause—B—longpause” indicates forward rotation FWD, while a detected sequence of“A—long pause—B—short pause” indicates backward rotation REV.

Adjustment of stride height SH and/or stride length SL may beaccomplished in various ways. Two preferred methods, which may beemployed individually or in combination, are (i) adjusting the angle ofincline of the guide rail 120, and (ii) adjusting the position of one ormore of the pivot points (not collectively referenced) about which anarm or link (not collectively referenced) pivots as the foot supports 70travel along the closed loop path of travel 70 p.

A wide variety of systems effective for adjusting the angle of inclineof the guide rail 120 are known to those skilled in the art. Exemplarysystems suitable for use in this invention are disclosed in U.S. PatentNo. Des. 372,282 issued to Passero et al., U.S. Patent No. Des. 388,847issued to Whan-Tong et al., U.S. Pat. No. 5,685,804 issued to Whan-Tonget al., U.S. Pat. No. 5,803,871 issued to Stearns et al., U.S. Pat. No.5,836,854 issued to Kuo, U.S. Pat. No. 5,836,855 issued to Eschenbach,U.S. Pat. No. 5,848,954 issued to Stearns et al., U.S. Pat. No.5,857,941 issued to Maresh et al., U.S. Pat. No. 5,882,281 issued toStearns et al., U.S. Pat. No. 5,882,281 issued to Stearns et al., U.S.Pat. No. 5,893,820 issued to Maresh et al., U.S. Pat. No. 5,938,568issued to Maresh et al., U.S. Pat. No. 5,957,814 issued to Eschenbach,U.S. Pat. No. 5,993,359 issued to Eschenbach, U.S. Pat. No. 5,997,445issued to Maresh et al., U.S. Pat. No. 6,042,512 issued to Eschenbach,U.S. Pat. No. 6,063,009 issued to Stearns et al., U.S. Pat. No.6,090,014 issued to Eschenbach, U.S. Pat. No. 6,126,574 issued toStearns et al., U.S. Pat. No. 6,146,313 issued to Whan-Tong et al., U.S.Pat. No. 6,168,552 issued to Eschenbach, U.S. Pat. No. 6,171,215 issuedto Stearns et al., U.S. Pat. No. 6,210,305 issued to Eschenbach, U.S.Pat. No. 6,254,514 issued to Maresh et al., U.S. Pat. No. 6,277,054issued to Kuo, U.S. Pat. No. 6,302,825 issued to Stearns et al., U.S.Pat. No. 6,334,836 issued to Segasby, U.S. Pat. No. 6,340,340 issued toStearns et al., U.S. Pat. No. 6,422,977 issued to Eschenbach, U.S. Pat.No. 6,440,042 issued to Eschenbach, U.S. Pat. No. 6,450,925 issued toKuo, U.S. Pat. No. 6,454,682 issued to Kuo, U.S. Pat. No. 6,554,750issued to Stearns et al., U.S. Pat. No. 6,612,969 issued to Eschenbach,U.S. Pat. No. 6,629,909 issued to Stearns et al., and U.S. PatentApplication Publication No. 2002/0019298 filed by Eschenbach, and U.S.Patent Application Publication No. 2002/0142890 filed by Ohrt et al,which disclosures are hereby incorporated by reference.

A wide variety of systems effective for adjusting the position of one ormore of the pivot points about which an arm or link pivots as the footsupports 70 travel along the closed loop path of travel 70 p are knownto those skilled in the art. Exemplary systems suitable for use in thisinvention are disclosed in U.S. Pat. No. 5,562,574 issued to Miller,U.S. Pat. No. 5,788,610 issued to Eschenbach, U.S. Pat. No. 5,836,854issued to Kuo, U.S. Pat. No. 5,836,855 issued to Eschenbach, U.S. Pat.No. 5,882,281 issued to Stearns et al., U.S. Pat. No. 5,893,820 issuedto Maresh et al., U.S. Pat. No. 5,895,339 issued to Maresh, U.S. Pat.No. 5,919,118 issued to Stearns et al., U.S. Pat. No. 5,921,894 issuedto Eschenbach, U.S. Pat. No. 5,957,814 issued to Eschenbach, U.S. Pat.No. 5,993,359 issued to Eschenbach, U.S. Pat. No. 6,027,430 issued toStearns et al., U.S. Pat. No. 6,027,431 issued to Stearns et al., U.S.Pat. No. 6,030,320 issued to Stearns et al., U.S. Pat. No. 6,045,488issued to Eschenbach, U.S. Pat. No. 6,053,847 issued to Stearns et al.,U.S. Pat. No. 6,077,196 issued to Eschenbach, U.S. Pat. No. 6,077,197issued to Stearns et al., U.S. Pat. No. 6,077,198 issued to Eschenbach,U.S. Pat. No. 6,080,086 issued to Stearns et al., U.S. Pat. No.6,090,013 issued to Eschenbach, U.S. Pat. No. 6,113,518 issued to Mareshet al., U.S. Pat. No. 6,135,923 issued to Stearns et al., U.S. Pat. No.6,171,215 issued to Stearns et al., U.S. Pat. No. 6,196,948 issued toStearns et al., U.S. Pat. No. 6,217,485 issued to Maresh, U.S. Pat. No.6,248,044 issued to Stearns et al., U.S. Pat. No. 6,248,045 issued toStearns et al., U.S. Pat. No. 6,248,046 issued to Maresh et al., U.S.Pat. No. 6,254,514 issued to Maresh et al., U.S. Pat. No. 6,277,054issued to Kuo, U.S. Pat. No. 6,283,895 issued to Stearns et al., U.S.Pat. No. 6,334,836 issued to Segasby, U.S. Pat. No. 6,338,698 issued toStearns et al., U.S. Pat. No. 6,361,476 issued to Eschenbach, U.S. Pat.No. 6,387,017 issued to Maresh, U.S. Pat. No. 6,390,953 issued to Mareshet al., U.S. Pat. No. 6,416,442 issued to Stearns et al., U.S. Pat. No.6,440,042 issued to Eschenbach, U.S. Pat. No. 6,450,925 issued to Kuo,U.S. Pat. No. 6,547,701 issued to Eschenbach, U.S. Pat. No. 6,554,750issued to Stearns et al., U.S. Pat. No. 6,565,486 issued to Stearns etal., U.S. Pat. No. 6,579,210 issued to Stearns et al., U.S. Pat. No.6,612,969 issued to Eschenbach, U.S. Pat. No. 6,629,909 issued toStearns et al., and U.S. Patent Application Publication No. 2001/0051562filed by Stearns et al., U.S. Patent Application Publication No.2002/0019298 filed by Eschenbach, U.S. Patent Application PublicationNo. 2002/0055420 filed by Stearns et al., and U.S. Patent ApplicationPublication No. 2002/0142890 filed by Ohrt et al., which disclosures arehereby incorporated by reference.

Other systems for adjusting stride height SH and/or stride length SLwhich may be utilized include specifically, but not exclusively, (a)adjusting the position of the foot supports 70 along the length of thefoot links 60, such as shown and described in U.S. Pat. No. 6,171,217issued to Cutler, the disclosure of which is hereby incorporated byreference (b) adjusting the position of the roller 69 along the lengthof the foot link 60, and (c) adjusting the lateral x and/or longitudinaly position of the drive shaft 30, such as shown and described in U.S.Pat. No. 6,146,313 issued to Whan-Tong et al., the disclosure of whichis hereby incorporated by reference.

One specific embodiment of a system for adjusting stride height SH andstride length SL is shown in FIGS. 1-4. This embodiment includes acombination of (i) a first pivot point repositioning unit 171 incommunication with the master control unit 140 and operably engaging thefoot link 60 and the connector link 90 so as to define the first endfoot link pivot point p₁ and permit repositioning of the first end footlink pivot point p₁ along the length of the foot link 60 and/or theconnector link 90 based upon a control signal from the master controlunit 140, and (ii) an incline adjustment system 130 in communicationwith the master control unit 140 and operably engaging the guide rail120 for changing the angle of incline of the guide rail 120 based upon acontrol signal from the master control unit 140.

This embodiment of a system for adjusting stride height SH and stridelength SL may also include (iii) a second pivot point repositioning unit(not shown) in communication with the master control unit 140 andoperably engaging the rocker link 80 and the connector link 90 so as todefine the rocker pivot point p₃ and permit repositioning of the rockerpivot point p₃ along the length of the rocker link 80 and/or theconnector link 90 based upon a control signal from the master controlunit 140, and (iv) a third pivot point repositioning unit (not shown) incommunication with the master control unit 140 and operably engaging thecrank arm 40 and the connector link 90 so as to define the crank pivotpoint p₄ and permit repositioning of the crank pivot point p₄ along thelength of the crank arm 40 and/or the connector link 90 based upon acontrol signal from the master control unit 140.

The alternative embodiment for supporting the second end portion 60 b ofeach foot link 60 to the frame 20 shown in FIG. 5 may include a pivotpoint repositioning unit 172 similar to the pivot point repositioningunit 171 shown in FIGS. 1-3 (shown in block format in FIG. 5) incommunication with the master control unit 140 and operably engaging thesecond end portion 60 b of the foot link 60 and the rear guide arm 121so as to define the second end foot link pivot point p₂ and permitrepositioning of the second end foot link pivot point p₂ along thelength of the foot link 60 and/or the length of the rear guide arm 121based upon a control signal from the master control unit 140.

Another specific embodiment of a system for adjusting stride height SHand stride length SL is shown in FIGS. 6-8. This embodiment includes acombination of (i) a pivot point repositioning unit 173 similar to thepivot point repositioning unit 171 shown in FIGS. 1-3 (shown in blockformat in FIGS. 6 and 7) in communication with the master control unit140 and operably engaging the foot link 60 and the front guide arm 221so as to define the first end foot link pivot point p₁ and permitrepositioning of the first end foot link pivot point p₁ along the lengthof the foot link 60 and/or the length of the front guide arm 221 basedupon a control signal from the master control unit 140, and (ii) alinear actuator 230 in communication with the master control unit 140with a first end of the linear actuator 230 attached to a fixed positionportion of the frame 20 and a second end the linear actuator 230attached to vertically adjustable portion of the frame 20 upon which thedrive shaft 30 is rotatably mounted, for permitting longitudinal yrepositioning of the drive shaft 30 relative to the fixed positionportion of the frame 20 based upon a control signal from the mastercontrol unit 140.

Yet another specific embodiment of a system for adjusting stride heightSH and stride length SL is shown in FIGS. 9-11. This embodiment includesa pivot point repositioning unit 174 similar to the pivot pointrepositioning unit 171 shown in FIGS. 1-3 (shown in block format inFIGS. 9 and 10) in communication with the master control unit 140 andoperably engaging the rocker link 320 and the second end 330 b of thedrawbar 330 so as to define a drawbar-rocker pivot point p₉ and permitrepositioning of the second end 330 b of the drawbar 330 along thelength of the rocker link 320 based upon a control signal from themaster control unit 140.

A master control unit 140 communicates with the incline adjustmentsystem 130, rotational direction sensing system 160, the pivot pointrepositioning unit 171, and the linear actuator 230 for receivingsignals from the rotational direction sensing system 160, processingthose signals to determine direction of travel of the foot supports 70,and adjusting the stride length SL and/or stride height SH of the closedloop path 70 p traveled by the foot supports 70 according to apreprogrammed adjustment in incline and/or pivot point locations, basedupon the direction of travel of the foot supports 70.

The master control unit 140 is also in communication with a userinterface panel 150 as is typical for stationary exercise equipment.

1. An exercise device comprising (a) a frame defining a transverse axis,(b) first and second foot supports operably associated with the framefor traveling in a forward and backward direction along a closed looppath relative to the transverse axis wherein the closed loop pathdefines a stride length, (c) a means effective for sensing the directionof travel of the foot supports along the closed loop path as between theforward and the backward directions, and (d) a means for automaticallyadjusting the stride length of the closed loop path traveled by the footsupports based upon the sensed direction of travel of the foot supports.2. The exercise device of claim 1 wherein the closed loop path is anelliptical path.
 3. The exercise device of claim 1 wherein (i) the footsupports are operably connected to the frame through a connecting systemhaving at least two members pivotally attached to one another at a pivotpoint, and (ii) the means for automatically adjusting the stride lengthof the closed loop path traveled by the foot supports, comprises (A) ameans for adjusting the pivot point along the length of at least onemember of the connecting system, and (B) a control unit in communicationwith the direction sensor and the stride length adjustment means forreceiving a signal from the sensor indicting the direction of travel ofthe foot supports along the closed loop path and automatically adjustingthe pivot point along the length of at least one member of theconnecting system based upon the received signal.
 4. The exercise deviceof claim 3 wherein the connecting system includes (i) first and secondfoot links each having a first end and supporting one of the footsupports, (ii) first and second connector links each having a first endand a second end, with each connector link pivotally attached proximatethe first end to one of the foot links proximate the first end of thefoot link at a foot link pivot point, (iii) first and second rocker armseach having a first end and a second end, with each rocker arm pivotallyattached proximate the first end to the frame and pivotally attachedproximate the second end to one of the connector links proximate thesecond end of the connector link at a rocker pivot point, (iv) a driveshaft rotatably attached to the frame, and (v) first and second crankarms having first and second ends, with each crank arm attachedproximate the first end to the drive shaft and pivotally attachedproximate the second end to the connector link at a crank pivot pointwhich is positioned intermediate the foot support pivot point and therocker pivot point.
 5. The exercise device of claim 1 further comprising(i) a guide rail, (ii) a transversely extending drive shaft rotatablyattached to the frame and extending along the transverse axis, (iii) anextension element extending away from the transverse axis and fixedlyattached to the drive shaft for unitary rotation with the drive shaft,and (iv) first and second foot links each supporting a foot support andhaving (A) first and second ends, (B) a first end portion pivotallyattached to the extension element at a point spaced from the transverseaxis for travel along a closed loop path relative to the transverseaxis, and (C) a second end portion supported by the guide rail forpermitting longitudinal travel of the second end portion of the footlink along a reciprocating path.
 6. The exercise device of claim 5wherein the guide rail is configured and arranged to impart a linearreciprocating path of travel to the second end portion of the foot linksas the foot supports travel along the closed loop path.
 7. The exercisedevice of claim 5 wherein the guide rail is configured and arranged toimpart a curved reciprocating path of travel to the second end portionof the foot links along the guide rail.
 8. The exercise device of claim1 further comprising (i) a guide arm pivotally attached to the frame,(ii) a transversely extending drive shaft rotatably attached to theframe and extending along the transverse axis, (iii) an extensionelement extending away from the transverse axis and fixedly attached tothe drive shaft for unitary rotation with the drive shaft, and (iv)first and second foot links each supporting a foot support and having(A) first and second ends, (B) a first end portion pivotally attached tothe extension element at a point spaced from the transverse axis fortravel along a closed loop path relative to the transverse axis, and (C)a second end portion pivotally supported by the guide arm forlongitudinal travel of the second end portion of the foot link along anarcuate reciprocating path.
 9. The exercise device of claim 5 whereinthe extension element is a drive pulley.
 10. The exercise device ofclaim 8 wherein the extension element is a drive pulley.
 11. Theexercise device of claim 5 wherein the extension element is a crankshaft.
 12. The exercise device of claim 8 wherein the extension elementis a crank shaft.
 13. The exercise device of claim 5 wherein the firstend portion of each foot link is directly pivotally attached to theextension element.
 14. The exercise device of claim 8 wherein the firstend portion of each foot link is directly pivotally attached to theextension element.
 15. The exercise device of claim 5 wherein the firstend portion of each foot link is indirectly pivotally attached to theextension element.
 16. The exercise device of claim 8 wherein the firstend portion of each foot link is indirectly pivotally attached to theextension element.
 17. The exercise device of claim 4 wherein the firstend portion of each foot link is indirectly pivotally attached to theextension element via an intermediate linkage system wherein theintermediate linkage system is (i) pivotally attached at a proximalpoint to the foot link, (ii) pivotally attached at a distal point to theframe, and (iii) pivotally attached to the extension elementintermediate the proximal and distal points of attachment.
 18. Theexercise device of claim 4 wherein (i) the first end of each foot linkis longitudinally spaced in a first longitudinal direction from thesecond end of the foot link, (ii) the second end of each foot link islongitudinally spaced in a second longitudinal direction from the firstend of the foot link, and (iii) the foot supports are supported by thefoot links at a position longitudinally spaced in the secondlongitudinal direction from the point at which the foot links aresupported by the guide rail.
 19. The exercise device of claim 4 whereinthe first end of each foot link travels along a circular path whichencompasses the transverse axis.
 20. The exercise device of claim 4wherein the first end of each foot link travels along a non-circulararcuate path relative to the transverse axis.
 21. The exercise device ofclaim 1 wherein the exercise device further comprises (A) right and leftlongitudinally extending foot links each slidably supporting a footsupport and having (1) a first longitudinal end portion pivotallyattached to the frame for travel along a first closed loop path about afirst transverse axis, and (2) a second longitudinal end portionpivotally attached to the frame for travel along a second closed looppath about a second transverse axis, (B) right and left rocker linkseach having a first portion operatively connected to a respective footsupport and a second portion pivotally mounted on the frame, and (C)right and left drawbars each having a first portion constrained totravel in association with the respective foot link relative to thefirst and second closed loop paths and a second portion connected to arespective rocker link, wherein the combination of a rocker link andassociated drawbar cooperate to transfer and link travel of the footlink along the first and second closed loop paths to longitudinalsliding of the respective foot support along the respective foot link.22. An exercise device comprising (a) a frame defining a transverseaxis, (b) first and second foot supports operably associated with theframe for traveling in a forward and backward direction along a closedloop path relative to the transverse axis wherein the closed loop pathdefines a stride height, (c) a means effective for sensing the directionof travel of the foot supports along the closed loop path as between theforward and the backward directions, and (d) a means for automaticallyadjusting the stride height of the closed loop path traveled by the footsupports based upon the sensed direction of travel of the foot supports.23. The exercise device of claim 22 wherein the closed loop path is anelliptical path.
 24. The exercise device of claim 22 wherein (i) thefoot supports are operably connected to the frame through a connectingsystem having at least two members pivotally attached to one another ata pivot point, and (ii) the means for automatically adjusting the strideheight of the closed loop path traveled by the foot supports, comprises(A) a means for adjusting the pivot point along the length of at leastone member of the connecting system, and (B) a control unit incommunication with the direction sensor and the stride height adjustmentmeans for receiving a signal from the sensor indicting the direction oftravel of the foot supports along the closed loop path and automaticallyadjusting the pivot point along the length of at least one member of theconnecting system based upon the received signal.
 25. The exercisedevice of claim 22 wherein the connecting system includes (i) first andsecond foot links each having a first end and supporting one of the footsupports, (ii) first and second connector links each having a first endand a second end, with each connector link pivotally attached proximatethe first end to one of the foot links proximate the first end of thefoot link at a foot link pivot point, (iii) first and second rocker armseach having a first end and a second end, with each rocker arm pivotallyattached proximate the first end to the frame and pivotally attachedproximate the second end to one of the connector links proximate thesecond end of the connector link at a rocker pivot point, (iv) a driveshaft rotatably attached to the frame, and (v) first and second crankarms having first and second ends, with each crank arm attachedproximate the first end to the drive shaft and pivotally attachedproximate the second end to the connector link at a crank pivot pointwhich is positioned intermediate the foot support pivot point and therocker pivot point.
 26. The exercise device of claim 22 furthercomprising (i) a guide rail, (ii) a transversely extending drive shaftrotatably attached to the frame and extending along the transverse axis,(iii) an extension element extending away from the transverse axis andfixedly attached to the drive shaft for unitary rotation with the driveshaft, and (iv) first and second foot links each supporting a footsupport and having (A) first and second ends, (B) a first end portionpivotally attached to the extension element at a point spaced from thetransverse axis for travel along a closed loop path relative to thetransverse axis, and (C) a second end portion supported by the guiderail for permitting longitudinal travel of the second end portion of thefoot link along a reciprocating path.
 27. The exercise device of claim26 wherein the guide rail is configured and arranged to impart a linearreciprocating path of travel to the second end portion of the foot linksas the foot supports travel along the closed loop path.
 28. The exercisedevice of claim 26 wherein the guide rail is configured and arranged toimpart a curved reciprocating path of travel to the second end portionof the foot links along the guide rail.
 29. The exercise device of claim26 wherein the means for automatically adjusting the stride height ofthe closed loop path traveled by the foot supports comprises a means foradjusting the angle of incline of the guide rail.
 30. The exercisedevice of claim 22 further comprising (i) a guide arm pivotally attachedto the frame, (ii) a transversely extending drive shaft rotatablyattached to the frame and extending along the transverse axis, (iii) anextension element extending away from the transverse axis and fixedlyattached to the drive shaft for unitary rotation with the drive shaft,and (iv) first and second foot links each supporting a foot support andhaving (A) first and second ends, (B) a first end portion pivotallyattached to the extension element at a point spaced from the transverseaxis for travel along a closed loop path relative to the transverseaxis, and (C) a second end portion pivotally supported by the guide armfor longitudinal travel of the second end portion of the foot link alongan arcuate reciprocating path.
 31. The exercise device of claim 30wherein the means for automatically adjusting the stride height of theclosed loop path traveled by the foot supports comprises a means foradjusting the distance between the point at which the guide arm ispivotally attached to the frame and the point at which the guide arm ispivotally attached to the second end portion of each foot link.
 32. Theexercise device of claim 26 wherein the extension element is a drivepulley.
 33. The exercise device of claim 30 wherein the extensionelement is a drive pulley.
 34. The exercise device of claim 26 whereinthe extension element is a crank shaft.
 35. The exercise device of claim30 wherein the extension element is a crank shaft.
 36. The exercisedevice of claim 26 wherein the first end portion of each foot link isdirectly pivotally attached to the extension element.
 37. The exercisedevice of claim 30 wherein the first end portion of each foot link isdirectly pivotally attached to the extension element.
 38. The exercisedevice of claim 26 wherein the first end portion of each foot link isindirectly pivotally attached to the extension element.
 39. The exercisedevice of claim 30 wherein the first end portion of each foot link isindirectly pivotally attached to the extension element.
 40. The exercisedevice of claim 25 wherein the first end portion of each foot link isindirectly pivotally attached to the extension element via anintermediate linkage system wherein the intermediate linkage system is(i) pivotally attached at a proximal point to the foot link, (ii)pivotally attached at a distal point to the frame, and (iii) pivotallyattached to the extension element intermediate the proximal and distalpoints of attachment.
 41. The exercise device of claim 25 wherein (i)the first end of each foot link is longitudinal spaced in a firstlongitudinal direction from the second end of the foot link, (ii) thesecond end of each foot link is longitudinal spaced in a secondlongitudinal direction from the first end of the foot link, and (iii)the foot supports are supported by the foot links at a positionlongitudinally spaced in the second longitudinal direction from thepoint at which the foot links are supported by the guide rail.
 42. Theexercise device of claim 25 wherein the first end of each foot linktravels along a circular path which encompasses the transverse axis. 43.The exercise device of claim 25 wherein the first end of each foot linktravels along a non-circular arcuate path relative to the transverseaxis.
 44. The exercise device of claim 23 wherein the exercise devicefurther comprises (A) right and left longitudinally extending foot linkseach slidably supporting a foot support and having (1) a firstlongitudinal end portion pivotally attached to the frame for travelalong a first closed loop path about a first transverse axis, and (2) asecond longitudinal end portion pivotally attached to the frame fortravel along a second closed loop path about a second transverse axis,(B) right and left rocker links each having a first portion operativelyconnected to a respective foot support and a second portion pivotallymounted on the frame, and (C) right and left drawbars each having afirst portion constrained to travel in association with the respectivefoot link relative to the first and second closed loop paths and asecond portion connected to a respective rocker link, wherein thecombination of a rocker link and associated drawbar cooperate totransfer and link travel of the foot link along the first and secondclosed loop paths to longitudinal sliding of the respective foot supportalong the respective foot link.
 45. An exercise device comprising (a) aframe defining a transverse axis, (b) first and second foot supportsoperably associated with the frame for traveling in a forward andbackward direction along a closed loop path relative to the transverseaxis wherein the closed loop path defines a stride length and a strideheight, (c) a means effective for sensing the direction of travel of thefoot supports along the closed loop path as between the forward and thebackward directions, and (d) a means for automatically adjusting thestride length and stride height of the closed loop path traveled by thefoot supports based upon the sensed direction of travel of the footsupports.
 46. The exercise device of claim 45 wherein the closed looppath is an elliptical path.
 47. The exercise device of claim 45 wherein(i) the foot supports are operably connected to the frame through aconnecting system having at least two members pivotally attached to oneanother at a pivot point, and (ii) the means for automatically adjustingthe stride length and stride height of the closed loop path traveled bythe foot supports, comprises (A) a means for adjusting the pivot pointalong the length of at least one member of the connecting system, and(B) a control unit in communication with the direction sensor and thestride length and stride height adjustment means for receiving a signalfrom the sensor indicting the direction of travel of the foot supportsalong the closed loop path and automatically adjusting the pivot pointalong the length of at least one member of the connecting system basedupon the received signal.
 48. The exercise device of claim 45 whereinthe connecting system includes (i) first and second foot links eachhaving a first end and supporting one of the foot supports, (ii) firstand second connector links each having a first end and a second end,with each connector link pivotally attached proximate the first end toone of the foot links proximate the first end of the foot link at a footlink pivot point, (iii) first and second rocker arms each having a firstend and a second end, with each rocker arm pivotally attached proximatethe first end to the frame and pivotally attached proximate the secondend to one of the connector links proximate the second end of theconnector link at a rocker pivot point, (iv) a drive shaft rotatablyattached to the frame, and (v) first and second crank arms having firstand second ends, with each crank arm attached proximate the first end tothe drive shaft and pivotally attached proximate the second end to theconnector link at a crank pivot point which is positioned intermediatethe foot support pivot point and the rocker pivot point.
 49. Theexercise device of claim 45 further comprising (i) a guide rail, (ii) atransversely extending drive shaft rotatably attached to the frame andextending along the transverse axis, (iii) an extension elementextending away from the transverse axis and fixedly attached to thedrive shaft for unitary rotation with the drive shaft, and (iv) firstand second foot links each supporting a foot support and having (A)first and second ends, (B) a first end portion pivotally attached to theextension element at a point spaced from the transverse axis for travelalong a closed loop path relative to the transverse axis, and (C) asecond end portion supported by the guide rail for permittinglongitudinal travel of the second end portion of the foot link along areciprocating path.
 50. The exercise device of claim 49 wherein theguide rail is configured and arranged to impart a linear reciprocatingpath of travel to the second end portion of the foot links as the footsupports travel along the closed loop path.
 51. The exercise device ofclaim 49 wherein the guide rail is configured and arranged to impart acurved reciprocating path of travel to the second end portion of thefoot links along the guide rail.
 52. The exercise device of claim 49wherein the means for automatically adjusting the stride length andstride height of the closed loop path traveled by the foot supportscomprises a means for adjusting the angle of incline of the guide rail.53. The exercise device of claim 45 further comprising (i) a guide armpivotally attached to the frame, (ii) a transversely extending driveshaft rotatably attached to the frame and extending along the transverseaxis, (iii) an extension element extending away from the transverse axisand fixedly attached to the drive shaft for unitary rotation with thedrive shaft, and (iv) first and second foot links each supporting a footsupport and having (A) first and second ends, (B) a first end portionpivotally attached to the extension element at a point spaced from thetransverse axis for travel along a closed loop path relative to thetransverse axis, and (C) a second end portion pivotally supported by theguide arm for longitudinal travel of the second end portion of the footlink along an arcuate reciprocating path.
 54. The exercise device ofclaim 53 wherein the means for automatically adjusting the stride lengthand stride height of the closed loop path traveled by the foot supportscomprises a means for adjusting the distance between the point at whichthe guide arm is pivotally attached to the frame and the point at whichthe guide arm is pivotally attached to the second end portion of eachfoot link.
 55. The exercise device of claim 49 wherein the extensionelement is a drive pulley.
 56. The exercise device of claim 52 whereinthe extension element is a drive pulley.
 57. The exercise device ofclaim 49 wherein the extension element is a crank shaft.
 58. Theexercise device of claim 52 wherein the extension element is a crankshaft.
 59. The exercise device of claim 49 wherein the first end portionof each foot link is directly pivotally attached to the extensionelement.
 60. The exercise device of claim 52 wherein the first endportion of each foot link is directly pivotally attached to theextension element.
 61. The exercise device of claim 49 wherein the firstend portion of each foot link is indirectly pivotally attached to theextension element.
 62. The exercise device of claim 52 wherein the firstend portion of each foot link is indirectly pivotally attached to theextension element.
 63. The exercise device of claim 48 wherein the firstend portion of each foot link is indirectly pivotally attached to theextension element via an intermediate linkage system wherein theintermediate linkage system is (i) pivotally attached at a proximalpoint to the foot link, (ii) pivotally attached at a distal point to theframe, and (iii) pivotally attached to the extension elementintermediate the proximal and distal points of attachment.
 64. Theexercise device of claim 48 wherein (i) the first end of each foot linkis longitudinal spaced in a first longitudinal direction from the secondend of the foot link, (ii) the second end of each foot link islongitudinal spaced in a second longitudinal direction from the firstend of the foot link, and (iii) the foot supports are supported by thefoot links at a position longitudinally spaced in the secondlongitudinal direction from the point at which the foot links aresupported by the guide rail.
 65. The exercise device of claim 48 whereinthe first end of each foot link travels along a circular path whichencompasses the transverse axis.
 66. The exercise device of claim 48wherein the first end of each foot link travels along a non-circulararcuate path relative to the transverse axis.
 67. The exercise device ofclaim 47 wherein the exercise device further comprises (A) right andleft longitudinally extending foot links each slidably supporting a footsupport and having (1) a first longitudinal end portion pivotallyattached to the frame for travel along a first closed loop path about afirst transverse axis, and (2) a second longitudinal end portionpivotally attached to the frame for travel along a second closed looppath about a second transverse axis, (B) right and left rocker linkseach having a first portion operatively connected to a respective footsupport and a second portion pivotally mounted on the frame, and (C)right and left drawbars each having a first portion constrained totravel in association with the respective foot link relative to thefirst and second closed loop paths and a second portion connected to arespective rocker link, wherein the combination of a rocker link andassociated drawbar cooperate to transfer and link travel of the footlink along the first and second closed loop paths to longitudinalsliding of the respective foot support along the respective foot link.